Tether ball



Aug. 20, 1968 D. M. CAPLAN 3,397,887

TETHER BALL Original Filed May 16, 1957 7727/5/45 sn s/vam /4 Eau/us 2x TENS/LE areal/67w 50044: x

INVENTOR. DAV/D M CAPAAM/ A rroe/va United States Patent 3,397,887 TETHER BALL David M. Caplan, Los Alamitos, Calif, assignor to W. J. Voit Rubber Corp., a corporation of California Continuation of application Ser. No. 13,468, Mar. 8, 1960, which is a division of application Ser. No. 659,616, May 16, 1957. This application Oct. 10, 1963, Ser. No.

3 Claims. c1. 273 ss This application is a continuation of application Ser. No. 13,468, filed Mar. 8, 1960, now abandoned, entitled Tether Ball, and the latter application is a division of my earlier application, Ser. No. 659,616, filed May 16, 1957, now abandoned.

The present invention relates to molded athletic balls and more particularly to balls known as tether balls and the like, as well as their methods of manufacture.

Such balls derive their name from the fact that they are designed to be suspended from a pole by means of a cord. While generally utilized for athletic purposes, such balls may also be used as floats for fish nets, boat bumpers, sewer balls and other purposes for which a tethered spherical object of this type may be useful.

In order to attach the cord to the ball, some means of attachment must be provided. As described in the prior art, one type of attachment means consists of a cavity, or recess, formed in the ball and a metallic insert imbedded in the wall of the ball and straddling the cavity so that a cord may be looped around such insert and any knot required to secure the cord is then placed in the cavity. In this way, the attaching means is not exposed upon the surface of the ball, and the likelihood of possible injury by contact with the knot is eliminated. Other types of attachment consist of a tethering ring projecting above the outer surface of the ball, with the ring being attached to the wall. Rings of this type use a plurality of strings made of synthetic fibers, such as nylon, for reinforcing the ring and for attaching it to the wall of the ball.

While balls of the type mentioned above have generally proved workable, certain disadvantages are encountered due, in part, to complexities in manufacture, detachment of the inserts, exposure of knots and creation of very hard areas on the surface of the ball in the vincinity of the cavity. When cords are used for reinforcing the projecting tether ring and then these cords are imbedded in the wall of the ball, the area containing the imbedded cords is also quite rigid. The cost is also high because of the amount of required manual labor.

According to this invention, the hanger of the 'ball is made of a blend of nitrile rubber and polyvinyl chloride dispersion resin, with the nitrile rubber formulation having a high percentage of carbon black for producing a proper tensile strength in the blend. The hanger is prermolded and pre-c-ured and then inserted into the mold whereupon the mold is partially filled with polyvinyl chloride plastisol and the ball is rotationally cast. The rotationally cast polyvinyl chloride wall of the ball makes a fusion and chemical bond with the flange of the hanger, thus attaching the wall to the hanger.

It is, therefore, an object of the present invention to provide a novel type of tetherball having a uniform wall and surface structure made of polyvinyl chloride plastisol and an integrally connected tether having a ring and a flange made of a blend of carbon black reinforced nitrile rubber and polyvinyl chloride, the cover of the ball and the flange of the tether being fused and chemically bonded to each other, thus forming one homogeneous, inseparable combination of the wall and its tether hanger.

Additional objects will be apparent from a consideration of the specification and drawings, in which:

FIGURE 1 is a side view of the completed ball;

3,397,887 Patented Aug. 20, 1968 FIGURE 2 is a side view of a preformed tether;

FIGURE 3 is a vertical cross-sectional view of a mold used for rotational casting of the ball;

FIGURE 4 is a transverse cross-section of the completed ball.

As illustrated in FIG. 1, the completed ball 10 is formed with tethering member 32 having an opening 12, a ring 11, and a flange 14. The lower surface 13 and the side surfaces 14a and 14b of the flange 14 become fused and chemically bonded to the surrounding portion of the balls wall 29 during the casting operation, thus producing a cast seamless, unitary structure in which the above mentioned surfaces of flange 14 become fused and chemically bonded to the cast wall during rotational casting and cuting of the resins. Grooves are molded into the wall during the casting operation. Flange 14 has a tapered edge portion 14a with an outer lip portion 14b formed therein. In order to obtain high tensile strength, the entire tether 32 is made of a composition including thermoplastic resin, such as polyvinyl chloride, and carbon black reinforced nitrile rubber. The same composition of nitrile rubber and vinyl is also suitable for making a prefabricated valve housing 15. This housing is shaped with an internal rib or shoulder 16 and an air outlet opening 17. This member is designed for receiving in its cavity a standard type of an air valve which is inserted into the cavity and retained therein by the internal rib member. A metal pin 25 sup ports the preformed valve housing within the mold during the fabrication of the ball. Pin 25 includes a body member 18 and grooved portion 19 shaped to conform to the interior of the valve housing. It is also provided with a projection 20 adapted to form or protrude through the air outlet opening in the valve housing. Pin 25 is also provided with an elongated, slightly tapered stem portion 21 which is inserted into a corresponding opening in the lower half 26 of the mold. The mold includes an upper half 27 and a lower half 26. The upper half 27 is provided with a recess 28 conforming to the shape of the tether member 11. The lower half 26 of the mold is also provided with a tapered opening for the insertion of the tapered stem 21.

In preparing for the casting of the ball, the preformed tether member is inserted into the recess 28 With the flange 14 extending into the mold cavity. The valve pin 25 is positioned within the lower half of the mold, and valve housing 15 is forced over the body portion 18 of this pin member as shown.

After the insertion of the valve housing and of the tether hanger, a predetermined quantity of a vinyl plastisol is introduced into the mold, the mold is closed and rotated in several planes while it is being heated to a maximum temperature of 370 F., in order to deposit a layer of vinyl plastisol upon the inner spherical surface of the mold, at the same time bonding the preformed tether and the valve housing by fusing and chemically bonding them to the deposited layer of the vinyl resin. Heating is continued at 360 F. for approximately eight minutes to complete the fusion of the vinyl compound while continuing the rotation in order to obtain gelation and fusion of the vinyl resin for obtaining a uniform high tensile strength structure. After cooling, the mold is opened and the completed seamless ball removed therefrom. After the valve member is inserted into the housing, the proper quantity of air is then introduced into the ball through this valve, thus completing the manufacturing steps of the ball. The structure of the resultant ball is shown in FIG. 4 with the tether and valve cap or housing integrally united to the wall of the ball.

While the foregoing description refers to the use of polyvinyl chloride plastisols, polyvinyl chloride organosols may also be used, in which case organic solvents are incorporated into the vinyl dispersion in order to modify flow properties and other characteristics.

With the Wall made of polyvinyl plasticizer, one obtains a wall, the physical properties of which resemble a wall made of natural leather having an outer surface with low coelficient of friction and a soft underpinning, thus pleasant to touch and free of hand sting typical of surfaces made of other synthetic materials.

The hanger, made of a blend of polyvinyl chloride and nitrile rubber, reinforced with carbon black, satisfies at once two requirements: tensile strength for supporting the ball, and forming an indestructible joint with the wall of the ball. The actual bond between the flange 14 and the wall 29 is either a chemical bond or a fusion, the chemical bond being the likelier of the two because the properties of the tether hanger after molding are those of a thermosetting material rather than thermoplastic. This bond is of such nature that it cannot be destroyed, for example, by trying to peel off flange 14 from wall 10. Nor is it possible to discern any line of demarcation between the flange and the wall. Since the flange is a wide flange, made of very strong material and the bond between it and the wall is indestructible, the stress produced on the hanger is distributed over a Wide area of the wall, rather than a small, localized area, with the result that the strain on the wall is much lower than that existing at the loop. An additional advantage of the structure resides in the fact that the hanger is made of a mixture of thermosetting material and thermoplastic material which exhibits the physical properties of the thermosetting material rather than those of the thermoplastic material. For example, its tensile strength does not appear to be materially affected by even very large changes in ambient temperature.

As to the bond between the nitrile-polyvinyl chloride blend and the polyvinyl chloride plastisol, this bond is enhanced, firstly, by the presence of polyvinyl chloride in both compositions and, secondly, because of the presence of a common plasticizer in both compositions. Therefore, because of these two common materials, there is an appearance of the chemical bond and also probably fusion,

the common plasticizer and polyvinyl chloride being instrumental for such bond.

What is claimed is: 1. A tetherball comprising: a spherical body portion of a fused polyvinyl chloride material,

a tether hanger extending significantly beyond the surface of said spherical body portion including a loop portion and a flange portion, said loop portion merging into said flange portion and said flange portion extending beyond the base of the loop portion, the hanger comprising a blend of carbon black reinforced nitrile rubber and polyvinyl chloride resin having a greater tensile strength than the tensile strength of said polyvinyl chloride spherical body portion and the hanger being mounted to the spherical body portion of the tetherball by means of a strong chemical and fusion bond securing the flange portion to the spherical body portion, said flange portion thereby distributing the tethering stress over a relatively large circular area of said spherical body portion, and

a valve member integrally mounted to the body portion of the tetherball for inflating said tetherball.

2. A tetherball comprising:

a Wall member of fused polyvinyl chloride plastisol having a recessed surface portion thereon, and

a tether hanger extending significantly beyond the surface of the wall member and being mounted thereto, said hanger including a loop and a flange formed of a blend of polyvinyl chloride resin and a nitrile rubber reinforced with carbon black, the blend having a tensile strength approximately twice as large as the tensile strength of the Wall member and the hanger being mounted to the wall member by a bond between the flange and the recessed portion of the wall member.

3. A tetherball in accordance with claim 2 wherein: the wall member includes a valve member integrally mounted thereto for inflating the tetherball, and the bond between the flange and the wall member is a chemical and fusion bond.

References Cited UNITED STATES PATENTS 2,115,926 5/1938 Hatton 273-58 2,858,249 10/1958 Crowley 27358 X 2,935,320 5/1960 Chupa 273-58 ANTON O. OECHSLE, Primary Examiner.

G. I. MARLO, Assistant Examiner. 

1. A TETHERBALL COMPRISING: A SPHERICAL BODY PORTION OF A FUSED POLYVINYL CHLORIDE MATERIAL, A TETHER HANGER EXTENDING SIGNIFICANTLY BEYOND THE SURFACE OF SAID SPHERICAL BODY PORTION INCLUDING A LOOP PORTION AND A FLANGE PORTION, SAID LOOP PORTION MERGING INTO SAID FLANGE PORTION AND SAID FLANGE PORTION EXTENDING BEYOND THE BASE OF THE LOOP PORTION, THE HANGER COMPRISING A BLEND OF CARBON BLACK REINFORCED NITRILE RUBBER AND POLYVINYL CHLORIDE RESIN HAVING A GREATER TENSILE STRENGTH THAN THE TENSILE STRENGTH OF SAID POLYVINYL CHLORIDE SPHERICAL BODY PORTION AND THE HANGER BEING MOUNTED TO THE SPHERICAL BODY PORTION OF THE TETHERBALL BY MEANS OF A STRONG CHEMICAL AND FUSION BOND SECURING THE FLANGE PORTION TO THE SPHERICAL BODY PORTION, SAID FLANGE PORTION THEREBY DISTRIBUTING THE TETHERING STRESS OVER A RELATIVELY LARGE CIRCULAR AREA OF SAID SPHERICAL BODY PORTION, AND A VALVE MEMBER INTEGRALLY MOUNTED TO THE BODY PORTION OF THE TETHERBALL FOR INFLATING SAID TETHERBALL. 